Unit for the preparation of fruits, berries and/or vegetables for the extraction of liquid raw products

ABSTRACT

For the extraction of juice pulp from fruits, berries and/or vegetables the raw material, which may consist of whole fruits, is first comminuted in a comminuting device (1) and subsequently squeezed out with the help of a press (2). Press (2) is constructed in such a way, that together with the juice separated from the raw material, a high proportion of valuable cell material is pressed off. Through this process a viscous juice pulp results, which subsequently is further processed for refining purposes, for example for the manufacture of clear juice, in a crossflow filtration device (7) which follows press (2). Through the process according to the invention the quality of the refined products as well as the economy of the unit and the yield are significantly improved, especially in connection with a recycling press (4) assigned to press (2).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a process for the preparation of fruits,berries and/or vegetables for the extraction of liquid raw products bycomminuting the raw material and separating the juice pulp.

2. Description of the Related Art

For the production of juice pulp (pulpy juice) as a preliminary step forfurther refining measures it is known to use so-called pulping machines.The raw material to be processed which can consist of whole fruits isfirst crushed and then the juice is extracted in the pulping machine. Inthe course of this the juice pulp consisting of juice and cell materialis separated from the seeds, stems, skins and cores by mechanical means.

This known process has the disadvantage that because of the intensivemechanical handling of the raw material in the pulping machine,especially in malaceous fruit. the stems, seeds and skin fragments aredamaged, thereby causing a negative impact on the taste and aroma of thejuice. Furthermore the residue consisting of stems, seeds, skins andcores which have been largely crushed by the pulping machine causesconsiderable difficulties in further extraction of juice by pressing.The overall yield is therefore smaller and the production of pulpyjuices is uneconomical.

Generally known are also the conventional processes for extracting fruitjuice by pressing. The object of these known methods is to achieve thehighest possible yield with the lowest possible dregs content. Becauseof the dregs content work is done with a small mesh size, which, forexample, in belt presses is about 0.5 mm. In this instance the finedregs and valuable cell material remain in the residue of the press andare lost. Moreover the layer thickness of the pressed raw material withconventional belt presses is relatively great (approximately 30 to 50mm). Because of this long juice paths are caused which do not letviscous cell material pass through which is needed for the extraction ofjuice pulp. The same is true for the passage openings in the separationwall between the juice which has flowed off and the residue, which aretoo small to let juice pulp through and would become clogged. Theconventional pressing processes are therefore not suitable for theextraction of juice pulp, which along with the juice that has beensqueezed out also still contains a large portion of cell material. Theraw juice extracted from conventional presses is further processedwithout any other liquefaction technology into clear or opaque juices,but not pulpy juices.

SUMMARY OF THE INVENTION

The object of this invention is to provide a process with appropriateequipment for extracting juice pulp, which along with a high degree ofeconomy and reduced investment costs, guarantees improved quality of thejuice pulp.

According to the invention this object is achieved in that juice pulpconsisting of juice and cell material is extracted by means of pressingthe comminuted raw material.

The advantages obtained with the invention consist particularly in thefact that by the gentle handling of the raw material during thepressing, stems, seeds and skin fragments of the fruit are not crushedand damaged. As a consequence an improvement in the quality of the juicepulp results. As a result of the large mesh size of the press accordingto the invention and the special design of the separation and sievesurfaces, fine dregs and cell material are carried off with the juicepulp. Therefore in the residue there remains less fine dregs and cellmaterial which favors the economical use of a recycling press forincreasing the yield. The strain on the conventional press functioningpreferably as a recycling press is thus greatly relieved by the pressaccording to the invention. As a result, the demands on the recyclingpress are not so high, so that it can be built more cheaply and theinvestment costs are reduced. Particularly well suited as recyclingpress are presses of the horizontal basket press type because of thelong flow paths which are necessary for the recovery of retentate fromthe crossflow filtration. As compared to conventional processes,particularly pressing processes, the yield is increased, since alongwith the juice more or less whole cells with the juice they contain arealso squeezed out. The construction of the press according to theinvention can be configured in a very simple and cost-saving mannerbecause of lesser demands as compared to conventional juice presses, forexample larger passage openings.

BRIEF DESCRIPTION OF THE DRAWING

The invention is explained in more detail in the following descriptionand drawing which represent various embodiments. There are shown in:

FIG. 1 a diagrammatic representation of the unit according to theinvention for the extraction of juice pulp,

FIG. 2 unit 1 according to FIG. 1 with a crossflow filtration deviceconnected downstream,

FIG. 3 a diagrammatic side view of a belt press for the extraction ofjuice pulp and

FIG. 4 a cross section through the belt press along line IV--IV in FIG.3 in an enlarged representation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the embodiment shown in FIG. 1 the raw material to be processed inthe form of whole fruits is introduced and communited in a comminutingdevice 1, which, for example, can be a mill. The mash thus obtained ispreferably treated with known mash enzymes, so that the individual cellswill separate better from the cell system. After that the treated mashis fed to a press 2 and squeezed out. Press 2 it is a press systemspecially developed for the extraction of juice pulp, which guaranteesan extremely gentle processing of the comminuted raw material. Thespecific construction characteristics of press 2 are explained later.From press 2 the extracted juice pulp, which consists of a pulpy liquidmass of juice and cell material, is conveyed to a refining device 3. Inrefining device 3 the juice pulp is further processed into pulpy juices,clear juice through filtration, dry products through drying, substratesto bioreactors, wine etc.

The residue remaining in press 2 is again squeezed out to improve theyield in a recycling press 4 assigned to press 2. The juice extracted isfed by a pipe 5 downstream from press 2 into the juice pulp.

A further embodiment of the invention is represented in FIG. 2. As inthe embodiment shown in FIG. 1 the raw material is comminuted in thecomminuting device 1 and conveyed to the press 2. For the treatment ofthe mash pectolytic enzymes are added to the raw material in dosedamounts before the comminuting. The juice pulp consisting of juice andcell material which has been separated from the comminuted raw materialin press 2 is conveyed over a pipe 6 of a crossflow filtration device 7,which consists of an ultrafiltration or a microfiltration device, and isprocessed into clear juice. In pipe 6 between press 2 and crossflowfiltration device 7 a treatment stage 8 is placed, in which the juicepulp is treated with juice enzymes in a known manner. The enzymetreatment achieves a reduction in the viscosity of the juice pulp andthereby an improvement in the filtering performance in crossflowfiltration device 7 which follows immediately downstream. In treatmentstage 8 or a further, subsequent treatment stage the juice pulp can befurther liquefied by various liquefaction techniques, for example byenzymatic, chemical or physical breaking down of the cells, before it isconveyed to crossflow filtration device 7. As in the unit shown in FIG.1, also in the embodiment shown in FIG. 2 the residue from press 2 isintroduced into recycling press 4 and squeezed out.

The juice extracted is fed by pipe 5 between treatment stage 8 andcrossflow filtration device 7 into pipe 6 or into the juice pulp. Afterthis the juice pulp is processed in crossflow filtration device 7 intoclear juice.

From crossflow filtration device 7 a pipe 9 leads to the recycling press4, to mix the retentate from the crossflow filtration with the residuefrom press 2 which is to be squeezed out for further use in recyclingpress 4. There it is suitable to place a preliminary treatment stage 10for the retentate in pipe 9 between crossflow filtration device 7 andrecycling press 4. In preliminary treatment stage 10 the retentate istreated in a known manner with cellulase and fining agents, before it isfed into recycling press 4.

FIG. 2 shows still another possibility for further processing the juicepulp extracted from press 2 into pulpy juices. As can be gathered fromthe representation in broken lines, from pipe 6 a further pipe 11branches off, which conveys the juice pulp to a colloidal mill 12 forexample. There the juice pulp is processed into pulpy juice in a knownmanner and subsequently is mixed with the juice from recycling press 4by branching off of a pipe 13 from pipe 5.

In FIG. 3 a specialized configuration of press 2 in the form of a beltpress is shown. From a drive drum 14 there runs a press belt 15 abouthorizontally to a press drum 16 and is led around the press drum 16 at abelt wrap alpha of about 280°. By a deflecting roller 17, press belt 15is led back to a drive drum 14. The raw material to be pressed andcomminuted is conveyed on the inner side of the horizontal segment ofpress belt 15 into the gap between the press belt and the outer surfaceof press drum 16. As can be seen from FIG. 4, a press layer 18 of theraw material results thereby, whose thickness d is approximately 3-20mm. Press layer 18 is relatively thin in comparison to conventional beltpresses, in which the press layer thickness is about 30 to 50 mm, sothat short juice paths result, which let pass through as high a portionas possible of viscous cell material along with the juice. In connectionwith the large belt wrap alpha of at least 250° a high specificeffectiveness of the press is achieved as to performance and yield.

Press belt 15 is designed as a sieve belt and forms a separation wall19, which is provided with openings 20, through which the juice pulp canflow off and be separated from the residue. The juice pulp extracted iscollected in a vat 21 placed underneath the press. The press residue,which leaves press drum 16 in the area of deflecting roller 17, ispicked up by a conveyor screw 22 placed underneath deflecting roller 17and carried off. In other embodiments separation wall 19 can also beformed by the wall of press drum 16. In this case press belt 15 can beclosed and openings 20 can be placed in the partition of press drum 16.

Openings 20 in separation wall 19 or in press belt 15 are maderelatively large in comparison with conventional belt presses, and arewidened in the direction of the press, so that an easier passage of theviscous juice pulp is made possible. Preferably the width of gap w ofopenings 20, especially in the processing of malaceous fruit, is about1.5 to 3 mm, while conventional belt presses show a gap width of onlyabout 0.5 mm. In contrast to known presses thickness S of separationwall 19 or else of press belt 15 is made relatively thin walled at 0.4to 1 millimeter, while the thickness in conventional belt presses isabout 2 mm. Through these measures according to the invention instancesof clogging of openings 20 are largely prevented and the performance ofthe press is enhanced.

A size ratio in the choice of the thickness d of press layer 18, gapwidth w of openings 20 and thickness S of separation wall 19 has provento be particularly effective and advantageous; in this ratio, presslayer thickness d is less than 15 times gap width w and gap width w ismore than 3 times thickness S of separation wall 19.

Since these features and characteristics produce high specific yields incomparison to known presses, which are used for conventional juiceextraction, there result for juice pulp extraction according to theinvention extremely simple and inexpensive presses. At the same timehigher yields are possible, since along with the juice whole cellscontaining juice are also pressed out, which in the course of theprocess according to the invention is extracted later on.

As a device for the extraction of juice pulp according to the inventionsimple belt press constructions are particularly well suited, which inthe sense of the cited features and characteristics are adapted to theprocess according to the invention. But with appropriate modificationseven other press systems can find use, if they show the features andcharacteristics according to the invention. Thus, for example, theprocess according to the invention can even be adapted to a diaphragmpress, in which the material to be pressed is pressed against a gapfilter or a sieve by means of a flexible diaphragm, with relatively thinlayers of material to be pressed. Such types of presses are not yet usedfor juice extraction in the above cited design. Through correspondingadaptation in line with the invention it is possible to work with thesepresses in a simple manner with thin press layers, which are necessaryfor carrying out the process according to the invention.

The process and the unit according to the invention can also be used toadvantage for the preparation of diverse raw materials from agriculturalproducts and wastes into substrates for biotechnological processes.

I claim:
 1. Unit for the preparation of fruits, berries and/orvegetables for the extraction of liquid materials therefrom comprising acomminuting device (1) into which are supplied the fruits, berriesand/or vegetables as raw materials to obtain mash, a connected press (2)to receive the mash and to extract therefrom juice pulp consisting ofjuice and cell material, means in said press (2) for separating thejuice pulp from a residue consisting of stems, seeds, cores and skinfragments such that a thin press layer (18) results to define a shortjuice path therethrough whereby a high portion of cell material ispassed through the press layer along with the juice, and a refiningdevice (3) to receive said extracted juice pulp, said means forseparating comprising a separation wall (19) in said press (2) for theseparating of said juice pulp and a residue, said separation wall (19)having openings (20) with a gap width (w), wherein said gap width (w) ismore than three times the thickness (s) of separation wall (19).
 2. Unitaccording to claim 1, wherein said press (2) is connected to a recyclingpress (4) in which the residue from press (2) is squeezed out and theextracted juice is conveyed to the juice pulp through a pipe (5) betweenpress (2) and refining device (3).
 3. Unit according to claim 2, whereinsaid recycling press (4) comprises a horizontal basket press.
 4. Unitaccording to claim 1 wherein said press (2) has connected thereto across-flow filtration device (7) to receive extracted juice pulp. 5.Unit according to claim 4, wherein said crossflow filtration device (7)comprises one of an ultrafiltration or microfiltration device.
 6. Unitaccording to claim 4 wherein the crossflow filtration device (7)produces a retentate which is conveyed back through a pipe (9) into arecycling press (4).
 7. Unit according to claim 6, wherein betweencrossflow filtration device (7) and recycling press (4) a preliminarytreatment stage (10) is provided, in which the retentate is treated withcellulase and fining agents.
 8. Unit according to claim 4 whereinbetween said press (2) and crossflow filtration device (7) a treatmentstage (8) is provided in which the juice pulp is treated with enzymes.9. Unit according to claim 1 wherein a device for the liquefaction ofthe juice pulp by enzymatic, chemical or physical breaking down of cellsis connected to said press (2) to receive extracted juice pulp.
 10. Unitaccording to claim 1 wherein to said press (2) there is connecteddownstream a colloid mill (12) for the extraction of pulpy juice. 11.Unit according to claim 10, wherein a recycling press (4) is connectedto said press (2) to receive residue therefrom and the juice extractedfrom recycling press (4) is conveyed through a pipe (13) to the pulpyjuice extracted from colloid mill (12).
 12. Device according to claim 1wherein thickness (d) of said press layer (18) is approximately 3 to 20mm.
 13. Device according to claim 1 wherein thickness (d) of press layer(18) is less than 15 times a gap width (w) of openings (20) which areprovided in a sieve belt (15) defining a separation wall (19) for theseparating of juice pulp and residue.
 14. Device according to claim 13,wherein gap width (w) of openings (20) is approximately 1.5 to 3 mm. 15.Device according to claim 13 wherein separation wall (19) shows athickness (s) of approximately 0.4 to 1 mm.
 16. Device according toclaim 13 wherein openings (20) in the separation wall (19) widen in thedirection of the press.
 17. Device according to claim 1 wherein saidpress (2) comprises a belt press.
 18. Device according to claim 17wherein the belt press exhibits a press drum (16), to which the rawmaterial is conveyed on the under side about horizontally, and pressbelt (15) is brought back after a belt wrap of at least 250° by adeflecting roller (17) to drive roller (14).
 19. Device according toclaim 18, wherein underneath deflecting roller (17) a conveyor screw(22) is placed for carrying away the pressing residue.
 20. Deviceaccording to claim 18 wherein separation wall (19) is formed by pressbelt (15) which is made as a sieve belt.
 21. Device according to claim18 wherein said separation wall (19) is defined by the wall of pressdrum (16).
 22. Device according to claim 1 wherein said press (2)comprises a diaphragm press.